Ingot mold and ingot



Feb. 26, 1924. 1,484,94Q

E. GATHMANN INGOT MOLD AND INGOT Filed Dec. 31 1923 Fatented Febo 26, T924.

,satt- EMIL GATHMANN, 0F BALTIMORE, MARYLAND.

INGOT MOLD AND INGU'JD.

Application filed. December 31, 1923. Serial No. 683,770.

timore, State of Maryland, have invented certain new and useful Impro ements in Ingot Molds and Ingots, of which the following is a specification.

This invention relates particularly to the casting of ingots from either steel which has been deoxidized as well as may be, or from partially deoxidized steel, and it involves certain improvements in the shape or contour of the mold chamber and of the ingot formed therein.

More especially my present invention relates to the contour of the horizontal cross sectional form of the mold chamber which is designed for so shaping the horizontal section of the ingot that the skin or outer surface thereof will be free at all times, during solidification of the ingot structure within the mold chamber, to contract and shrink awa from the mold chamber walls without mec anical binding or tying of the ingots surface to the mold chamber walls, the contour of the mold chamber being of such form that the ingot will have a cross section readily reduceable by rolling mill or forge action, with the assurance of a minimum of cracking, seaming or like flaws in the bloom, billet or other shape of product produced therefrom. My improvements may obviously be embodied in either big-end-np, parallel chamber walled, or big-end-down molds. I

My present improvements contemplate certain refinements of the molds and ingots shown, described and claimed in my Patent No. 1340,5355 of J an. 2, 1923.

In the accompanying drawings Figure 1 shows a vertical section of an ingot mold of the big-end-down type constructed according to my invention.

Figure 2 is a view on an enlarged scale and in section on lines 2-2 of Figure 1, the

outer portion of the mold walls being broken away for convenience of illustration.

Figure 3 is a perspective view of an ingot formed in a mold having a chamber of the kind shown in'Figur'e 2. The inner walls of the mold chamber are shaped as shown and indicated in Figures 1 and 2 with a plurality of vertically extending salients of the kind hereinafter explained. These salients preferably extend from top to bottom of the mold chamber or into a necked-in portion of the mold and,

merge or disappear therein as shown.

The mold M as shown in Figure 1 is a big-end-down mold of a necked-in ty e. The necked-in or contracted part N of tie mold chamber isat the top of the mold instead of at the bottom as would be the case in a b-ig-end-up chamber type of mold of this construction.

The contour of the mold chamber corners is similar to that shown in my Patent No. 1,440,535 of'Janua-ry 2, 1923, but difiers therefrom in the primary wall contour and in certain other parts hereinafter specified and claimed.

In the usual practice-after the ingot has been formed in its mold and has been stripped therefrom, it is re-heated in a soaking pit or furnace. When taken from the pit or furnace for desired reduction of its cross section, an ingot is merely a heated steel casting and is relatively tender and liable to surface cracks or splits if subjected to any very heavy blows or severe stresses, which defects are more likely to occur if initial strains or defects are produced by the mold chamber walls tying to the ingot during its solidification and accompanying contraction.

In 111 patent of January 2, 1923, above referre to, T have shown an ingot mold for producing ingots with novel or difierential useful in the formation of ingots made from eifervescing, rising or semi-piping steels.

For forming ingots of well-deoxidized or de-gassified steels, where interior soundness of product is specified as well as surface soundness, I prefer to employ the so-called corner construction, and reference is made big-end-up type of mold as shown in patents'previously granted to me.

The general kind of corners of the mold chamber and cross section of in ot now employed by me is similar to that s own in 111 patent of January 2, 1923., T have foun however, that certain further refinements and modifications in the cross section of the mold cavity and shape of the salients are advantageous. As shown in Figure 2 of the drawing, the mold chamber C is given four substantially straightdined or plane. surface primary walls or sides A, the opposite walls being substantially parallel and the adjacent primary walls extending at approximately ninety degrees from the plane of the others. Eight straight secondary walls B are shown connected to each other and to the primary walls by twelve arc-shaped parts or salients S. T have found from actual experiments that each secondary wall B should extend at an angle of between 5 and 15 from a tangent T (Fig. 2) parallel to an adjacent primary wall, the distance from one primary wall to an opposed primary wall being thus greater than the distance from one secondary wall to a secondary wall on the opposite side of the mold chamber.

The principal advantages of this construction are that all the vertically extending outer walls and the cross sectional contour of an ingot formed in this contour of mold chamber will, upon solidification of the skin or outer portion of the ingot formation as shown at I, in Figure 3, be free and unimpeded to move out of contact'with the chamber walls of the mold upon the considerable shrinkage which takes place in the cross section of the ingot during its solidification. This is largely due to the fact that the opposite side walls or primary walls A are straight or substantially straight, while the corner walls B converge inwardly from the planes of the straight primary walls.

The ingot surface contour in my improved construction solidifies and contracts without danger of mechanical catches or restraints 'due to binding or hanging in the mold chamber occurring during solidification and contraction, and mechanically produced cracks in the ingot skin or surface are thus prevented or at any rate greatly reduced. After the ingot as shown in Figure 3 has been stripped or removed from the mold, it is placed in a soaking pit, as previously stated, and re-heated for rolling or other types of working or reduction of area into finished or semi-finished shapes. The corners or salients S (Fig. 3) being wide, preferably 100 or more, there ,is lessened danger of overheating or burning of any portion of the ingot surface. than ordinarily.

The type of cross section of ingot ll as shown in Figure 3, which is produced in a mold chamber of the cross section shown in Figures 1 and 2, allows of reduction with lessened danger of over-lapping of corners or salients of the ingot during the-initial reduction in a manner similar to that described in my patent of January 2, 1923. In Figure 3, primary faces of the ingot I are shown at A, secondary faces at B, and salients or corners at S.

As the widened corners or secondary sldes .B' of the ingot are not usually directly acted upon by the initial passes of the mill, press or hammer, and as the bulk of the work, by reason of its larger cross section, is initially upon the primary walls or sides A of the ingot, working cracks, seams, laps at the corners and like defects are prevented or at least greatly reduced in the product shaped from my improved section of ingot as described. I

Tngots as shown in Figure 3 may thus be formed or shaped with lessened danger of hanging or mechanical bindin in mold chambers, and can be more uniformly reheated and worked to shape of product desired with lessened danger of overlapping and other reduction flaws and seams than is possible with any other known ingot surface contours.

The exact angular disposition of the secondary walls B and the salients S may be varied somewhat for different products or specifications, but I have found that the best practice is obtained from the approximate dimensions shown 'in Figure 2 of the drawing, in which the secondary or corner walls 18 are shown as inclining inwardly between from approximately 5 to 15 from adjacent primary walls A and where the salients S of the mold chamber are formed by arcs greater than 45 and the intermediate salients S connecting the primary and secondary walls are formed by arcs of less than 45.

The secondary or corner walls B may, if desired, be made of a slightly corrugated or fluted contour, but the primary walls A should consist of substantially straight or plane surfaces.

The width of the primary walls is optional, but I prefer to make them equal to approximately one-third of the horizontal section of the ingot.

The solidification of the ingot is primarily due to the escape of heat from the molten metal at its outer or vertically extending side portions which are initially in contact with the mold chamber walls. The interior of the ingot within the enclosing side'portions remains molten for a considerable period after said outer portion has solidified into what is termed the ingot structural skin or envelope. This outer skin of the ingot during solidification contracts considerably and the cross section of the ingot as a whole thus becomes smaller than the cross,

section of the mold chamber in which it was formed. The skin shrinkage amounts to as much as one tenth of an inch per foot in forty carbon steel and progresses first from the corner salients S and the secondary walls B and is then centralized at the mid-section mean to of the mold chamber to the middle of the side walls, more or less binding does occur at the end portions of said salients.

A round cross section of the ingot mold chamber would seem to be the best to as sure freedom from mechanical binding during solidification and shrinkage of the ingot, but inasmuch as around in ct would crack on its free sides during rol ing or forging reductions, molds producing corrugated ingots have been used to obtain a great extent of freedom in separation of the ingot from the mold walls durin the shrinkage of the ingot while solidifying. Such corrugated ingots are, however, more diiiicult to reduce in cross section in mill practice than. ingots of rectangular cross section.

My new construction of mold chamber and ingot has most of the advantages of the round or ordinary polygonal in 0t in freedom of shrinkage during solidi cation and all of the advantages of a rectangular ingot during reduction of section in mill practice.

' I claim as my invention:

' 1. An ingot mold having a chamber any cross section of which below the neck is provided with curved salients at the corners which merge on each side into relatively narrow, substantially straight inclined corner walls in turn merging into relatively wide substantially straight centrally located walls.

2. An ingot mold having a chamber provided with outwardly extending curved salients at the corners and with smaller outwardly extending curved salients which connect the ends of said corner salients with relatively narrow inclined corner walls which are connected by small outwardly extending salients with relatively wide substantially straight side walls. a

3. An ingot mold havmg an ingot shaping chamber defined by a cross sectional contour consisting of four primar and eight secondary walls or sidesand aving four rounded corners or salients, each corner salient being formed by an are greater than 45 and eight intermediate salients, the arc of each of which is less than 45.

4. An ingot mold with a chamber having four primary side walls and eight secondary or corner walls connected to the pri* 1 mary side walls by arc-shaped corners or salients, each secondary wall extending at an angle of between 5 and 15 from a tangent which is parallel to a line connecting with an adjacent primar wall.

5. An ingot mold having a chamber provided with corner salients and four primary side walls at least two of which are substantially straight and parallel one with the other, a plurality of secondary walls intervening between the said primary wall and the corner salient-s of the chamber, the arc of each corner of the mold being subtended by an angle greater than 90.

6. A mold having a chamber provided with two pairs of substantially parallel straight primary side walls, one pair, of said walls being disposed at approximately 90 from the ad'acent pair of walls, and with eight secon ary or corner walls, each secondary wall being connected to an outwardly extending curved salient.

7. A mold having a chamber provided with four primary side walls of a substantially plane or straight contour and with widened corners, each corner being provided with three outwardly extending curved salients, which intervene between two primary side walls.

8. An ingot having four primary side walls of substantially plane or straight contour and a plurality of secondary or corner walls connected to the primary walls by areshaped parts or salients, each secondary wall extending at an angle of from 5 to 15 from a tangent to an adjacent primary wall.

9. An ingot formed with a plurality of substantially straight primary walls and a plurality of secondary walls intervening between the primary walls, the secondary walls at each corner of the ingot being connected with each other by outwardly extending curved salients formed by arcs of more than 45 and connected with the adjacent primary walls by outwardly extending curved salients having arcs of less than 45.

10. An ingot mold with a chamber having four primary side walls and a plurality of secondary or corner walls connected to the primary walls by are shaped portions or salients, each secondary wall extending at an angle of from 5 to 15 from a line connected with and extending from said primary wall.

11. A mold having a chamber provided with a plurality of substantially straight primary side walls and with widened corners, each cornerbeing provided with three outwardlyextending salients which intervene between two primer side walls.

12. A mold having a c amber provided with a plurality of substantiall straight primary side walls and with wi ened corners, each corner being provided with three outwardly extending curved salients which intervene between .two primary side walls.

43: v meaeao 13. A mold having a polygonal chamber rectangular cross section provided with four to of substantially rectangular cross section substantially straight primary side walls provided with four relatively wide substanand with four widened corners, each having tially straight primary side walls and with two substantially straight corner walls and 5 widened corners, each corner being prothree outwardly extending salients.

vided with two relatively narrow corner walls In testimony whereof, I have hereunto 1K5 anld with three outwardly extending curved subscribed my name. sa ients.

M. A polygonal ingot of substantially EMIL GATHMANN. 

